How can I watch a variable in Ruby Pry?

Question

I'm using Ruby 2.2.2, Pry and 'pry-byebug'. The continue statement removes any watched variables in have in pry-byebug:

[1] pry(main)> watch foo
Watching foo
watch: foo => 42
[2] pry(main)> watch
Listing all watched expressions:

1: foo => 42

[3] pry(main)> continue
[1] pry(main)> watch
No watched expressions

Losing them on every continue makes watched expressions pretty worthless. If I use next and step to the same point in the code instead, the watched expressions are still there; it's just the continue that causes the problem. At the moment I can't even find any documentation on the watch statement, so I don't know why this occurs.

More generally, I just want to print out the value of a set of expressions on every Pry prompt (or, perhaps, print them out if they've changed since the last time they were printed.) How can I achieve this in a Ruby debugger?

Answer 1

Using pry-moves you can use watch variable - this will display value of variable on each step.